“…It is now well known that outflows can be accelerated from an accretion disk ("Disk wind", Blandford & Payne 1982, Pelletier & Pudritz 1992, Fiege & Henriksen 1996, Contopoulos & Lovelace 1994, Ferreira & Pelletier 1993, Ferreira 1997, Vlahakis & Tsinganos 1998, Lery et al Lery et al 1999b), or at the disk-magnetosphere boundary ("X-winds", Shu et al 1988Shu et al , 1994. Therefore, a Keplerian rotation profile is one of the most realistic description for rotation of sources producing jets.…”